public class Sy3_2 {
    public double getArea(double r)
    {
        System.out.print("圆形面积：");
        return 3.14*r*r;
    }
    public  double getArea(double a,double b)
    {
        System.out.print("矩形面积：");
        return a*b;
    }
    public double getArea(double a,double b,double c)
    {
        System.out.print("三角形面积：");
        double p=(a+b+c)/2;
        return Math.sqrt(p*(p-a)*(p-b)*(p-c));
    }
}
